The purpose of this study is to test the prospective relationship of post-traumatic stress disorder (PTSD) to day and night time ambulatory blood pressure (ABP) and thus, risk for hypertension and incident cardiovascular disease (CVD). PTSD occurs consequent to trauma and is characterized in part by hyperarousal, emotional dysregulation, and poor sleep, with a 50% greater risk for CVD, independent of traditional risk factors. Large cohort studies report greater prevalence of hypertension, including our n=200,000 pilot analyses, which also show that PTSD treatment may attenuate this risk. Critical questions concern early detection of hypertension risk, and whether PTSD treatment reduces this risk. Ambulatory blood pressure (ABP) is a better predictor of CVD risk than is the clinic blood pressure of 140/90mmHg on which a diagnosis of hypertension is made. ABP monitoring combined with ecological momentary assessment (EMA) by electronic diary creates a powerful tool, and using this we have found that momentary ratings of anger and anxiety are highly correlated with momentary elevations in blood pressure (BP). When combined with night time actigraphy, another powerful tool is created whereby the effects of sleep on ABP can be determined. These tools together may be particularly useful for testing the prospective relationship of PTSD to ABP and thus CVD risk, since among the hallmarks of PTSD are heightened emotional reactivity to daily events, and disrupted sleep. Leveraging the resources of our recently funded Women Veterans Cohort Study-Wave 2 and our National Center for PTSD, we propose to study 300 recent military veterans with and without a PTSD diagnosis (N=150 each) on 2 occasions, 2-years apart. We hypothesize that, 1) those with vs. without PTSD at baseline will show a greater 2-year increase in day and night time ABP, and 2a) will have a greater ABP response to both momentary negative emotion and PTSD symptoms, and poorer actigraphy-assessed sleep; 2b) negative emotions/PTSD symptoms and poor sleep will in part mediate the prospective association of PTSD to day and night time ABP; 3) improvement in PTSD from baseline to follow-up (e.g., due to PTSD treatment or natural trajectory), will be associated with a decrease or smaller increase in ABP over the 2 years. Upon completion of baseline assessments we will evaluate the cross-sectional relationships of PTSD status and symptom severity to: 1) day and night time ABP, 2) the proportion of EMA reports with PTSD symptoms endorsed 3) mean levels of EMA-reported negative affect, and 4) poor sleep. We will also analyze the effect of poor sleep - short duration, efficiency - on, 1) momentary negative emotions and PTSD symptoms, and 2) the relationship of momentary negative emotions and PTSD symptoms to ABP. Significance. The proposed study will point the way toward risk mitigation clinical trials, whether they test the targeted use of ABPM according to threshold PTSD symptoms, aggressive PTSD treatment, and/or early intervention with pharmaceutical, behavioral, or combined strategies for treating elevated day or night time ABP among individuals with PTSD.